title: The Drosophila peptidoglycan-recognition protein LF interacts with peptidoglycan-recognition protein LC to downregulate the Imd pathway.
abstract: The peptidoglycan (PGN)-recognition protein LF (PGRP-LF) is a specific negative regulator of the immune deficiency (Imd) pathway in Drosophila. We determine the crystal structure of the two PGRP domains constituting the ectodomain of PGRP-LF at 1.72 and 1.94 Å resolution. The structures show that the LFz and LFw domains do not have a PGN-docking groove that is found in other PGRP domains, and they cannot directly interact with PGN, as confirmed by biochemical-binding assays. By using surface plasmon resonance analysis, we show that the PGRP-LF ectodomain interacts with the PGRP-LCx ectodomain in the absence and presence of tracheal cytotoxin. Our results suggest a mechanism for downregulation of the Imd pathway on the basis of the competition between PRGP-LCa and PGRP-LF to bind to PGRP-LCx.
authors.affiliation: Centre de Biophysique Moléculaire, UPR 4301 CNRS, Rue Charles Sadron, Orléans 2 45071, France.
authors.forename: Nada
authors.initials: N
authors.lastname: Basbous
authors.forename: Franck
authors.initials: F
authors.lastname: Coste
authors.forename: Philippe
authors.initials: P
authors.lastname: Leone
authors.forename: Renaud
authors.initials: R
authors.lastname: Vincentelli
authors.forename: Julien
authors.initials: J
authors.lastname: Royet
authors.forename: Christine
authors.initials: C
authors.lastname: Kellenberger
authors.forename: Alain
authors.initials: A
authors.lastname: Roussel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010457:Peptidoglycan / Q000378:metabolism; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D020349:Surface Plasmon Resonance
chemical_list: D002352:Carrier Proteins; D029721:Drosophila Proteins; D010457:Peptidoglycan; C439909:imd protein, Drosophila; C118897:peptidoglycan recognition protein